EEG system for time-scaling presentations

• US 20040073129A1
• Filed: 10/15/2002
• Published: 04/15/2004
• Est. Priority Date: 10/15/2002
• Status: Abandoned Application

• Current Assignee: SSI Corporation
• Original Assignee: SSI Corporation
• Inventors: Ogawa, Yoku, Tanaka, Taka-aki, Caldwell, Samuel J.
• Application Number:
  US10/272,514
• Publication Number:
  US 20040073129A1
• Time in Patent Office: Days
• US Class Current: 600/544
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]
• CPC Class Codes: A61B 5/375 using biofeedback
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/6816 Ear lobe

Abstract

A data acquisition unit for an EEG system includes pliant electrodes and/or a wireless transmitter that permit use of the EEG system without electrolyte gels or solutions and/or connecting wires. The electrodes can use a conductive fabric or a conductive rubber material that is dry or damp and mounted in a rigid structure that plugs into a socket on a headset. A feedback unit in the EEG system, which receives and processes the data from data acquisition unit, can be a high power, high performance processing system that implements complex feedback presentations and control functions based on analysis of the EEG data. In one embodiment, the feedback system controls a presentation player and adjusts a playback rate according to the sensed brain activity or synchrony between left and right brain activity. A PWM signal can control the time scale of the presentation.

Claims

1. A system comprising:

headgear;

a first sensing electrode mounted on the headgear so as to contact a forehead of a user wearing the headgear, the first sensing electrode being a pasteless electrode that is pliable;

a second sensing electrode for use as an electrical contact to the user; and

an amplifier connected to the first and second sensing electrodes, the amplifier producing a signal that depends on a difference between potentials of the first and second sensing electrode.

2. The system of claim 1, further comprising a wireless transmitter connected to the amplifier to transmit data representing the signal.

3. The system of claim 2, further comprising a feedback unit that includes:

a wireless receiver capable of receiving the data from the wireless transmitter; and

a processor coupled to receive the data from the wireless receiver.

4. The system of claim 1, wherein the second sensing electrode comprises a clip suitable for clipping to an ear of the user.

5. The system of claim 4, further comprising a third sensing electrode, the third electrode being a pasteless, pliable electrode that is mounted on the headgear so as to contact the forehead of the user wearing the headgear.

6. The system of claim 5, wherein the amplifier is connected to the first, second and third electrodes.

7. The system of claim 6, further comprising a second amplifier producing a signal that depends on a difference between potentials of the third and second sensing electrodes.

8. The system of claim 5, further comprising a fourth electrode, the fourth electrode being a pasteless, pliable electrode that is mounted on the headgear so as to contact the forehead of the user wearing the headgear, wherein the fourth electrode contacts a portion of the forehead that is between portions that the first and third electrodes contact.

9. The system of claim 8, wherein the amplifier is a dual channel differential balanced amplifier connected to use a signal from the fourth electrode as a shared reference.

10. The system of claim 1, wherein the first electrode is a dry electrode.

11. The system of claim 1, wherein the first electrode is dampened with water.

12. The system of claim 1, wherein the signal comprises a brain activity signal.

13. The system of claim 1, wherein the headgear comprises a socket into which the first electrode is plugged for use, the first electrode being removable from the socket.

14. The system of claim 13, wherein the first electrode comprises:

a rigid structure;

a compressible backing in the rigid structure; and

a conductive material attached to the compressible backing.

15. The system of claim 14, wherein the conductive material comprises a conductive fabric.

16. The electrode of claim 14, wherein the conductive material comprises a conductive rubber material.

17. The electrode of claim 14, wherein the rigid structure includes a cup in which the compressible backing resides, the cup having a shape that fits into the socket.

18. An electrode for an EEG, comprising:

a rigid structure;

a compressible backing in the rigid structure; and

a conductive material attached to the compressible backing.

19. The electrode of claim 18, wherein the conductive material comprises a conductive fabric.

20. The electrode of claim 18, wherein the conductive material comprises a conductive rubber material.

21. The electrode of claim 18, wherein the compressible backing comprises foam rubber material.

22. The electrode of claim 18, wherein the rigid structure includes a cup in which the compressible backing resides.

23. An EEG system comprising a sensing electrode made of a conductive rubber material.

24. The EEG system of claim 23, further comprising a headset in which the sensing electrode is mounted so as to contact a user'"'"'s head.

25. A presentation system comprising:

a player that is capable of playing presentations at an adjustable time scale; and

a sensor connected to sense brain activity of a user and to provide to the player a control signal that depends on the brain activity sensed.

26. The system of claim 25, further comprising a headset on which the sensor is mounted, the headset positioning the sensor in proximity to the head of the user.

27. The system of claim 25, wherein the control signal comprises a pulse width modulated signal.

28. The system of claim 27, wherein a pulse width of the pulse width modulated signal controls a time scale at which the player plays a presentation.

29. The presentation system of claim 25, wherein the sensor comprises:

a headset containing a data acquisition unit; and

a feedback system that receives and processes a brain activity signal from the data acquisition, the feedback system generating an observable representation of the brain activity of the user.

30. The system of claim 25, wherein the control signal has a level that depends on synchrony between brain activity measured for a left side of a user'"'"'s head and brain activity measured for a right side of the user'"'"'s head.

31. A method for controlling a presentation system comprising:

measuring a left signal representing brain activity from a left side of a user'"'"'s head while the user senses a presentation;

measuring a right signal representing brain activity from a right side of the user'"'"'s head while the user senses the presentation; and

setting a play rate of the presentation according to synchrony between the first and second signals.

32. The method of claim 31, further comprising measuring synchrony between the left and right signals.

33. The method of claim 32, wherein measuring synchrony comprises:

identifying a left frequency that corresponds to a frequency component that has the greatest amplitude within a selected band of the left signal;

identifying a right frequency that corresponds to a frequency component that has the greatest amplitude within the selected band of the right signal; and

comparing the left and right frequencies.

34. The method of claim 33, wherein comparing comprises determining if the left frequency has a brainwave type that matches a brainwave type of the right frequency.

35. The method of claim 33, wherein comparing comprises determining whether the left frequency is equal to the right frequency.

36. The method of claim 35, wherein comparing further comprises determining whether the component corresponding to the left frequency has a phase angle with a sign that is equal to a sign of a phase angle of the component corresponding to the right frequency.